Tight House races: Late update

From NBC News' Doug Adams
Two days after the election, nine (or 10) House races still have not been decided. All of the seats are held by Democratic incumbents -- and in four of the races, the Republican challenger is ahead. Below is an update and analysis of each race as of Thursday afternoon.

Arizona 8th CD: Two-term incumbent Gabrielle Giffords (D) leads by 2,356 votes over challenger Jesse Kelly, a 29-year-old Marine veteran and Tea Party favorite. Giffords' lead is just under 1 percentage point as of Thursday late afternoon. Democrats are confident she can hang on, as her lead has increased slowly each day. The bulk of the remaining early and provisional ballots are in Pima County (Tucson), which Giffords won decisively. The 8th Congressional District is the southeast corner of Arizona and includes almost all of Tucson.

California 11th CD: This is the closest race in the country. Two-term Rep. Jerry McNerny (D) leads by a scant 121 votes over Republican David Harmer, out of more than 164,000 votes cast. Tens of thousands of mail-in and provisional ballots remain to be counted, and a result isn't expected for at least a week. Republicans are optimistic they could pull off a win here because Harman was winning a bigger percentage of the early mail-in vote before Election Day. Either candidate can demand and pay for a recount, but that decision must be made by Dec. 5. The sprawling 11th Congressional District is in the San Joaquin valley and includes part of Stockton.

California 20th CD: Three-term incumbent Jim Costa (D) trails challenger Andy Vidak, a cherry farmer, by less than 2,000 votes out of more 60,000 votes cast. But there are still at least 50,000 absentee and provisional ballots still outstanding. Democrats are cautiously optimistic that the moderate Costa can pull it out since the bulk of the outstanding ballots come from two counties (Fresno and Kern) that Costa won convincingly. Election officials have until Nov. 30 to produce final results, so we may not know the winner in this one until after Thanksgiving at the earliest. The rural 20th Congressional District is in central California, southwest of Fresno.

Illinois 8th CD: Incumbent Melissa Bean (D) was heavily favored in this race, but now finds herself trailing by 553 votes with 100 percent of the precincts reporting. Republican newcomer Joe Walsh -- a self-employed consultant who calls himself a Tea Party activist -- has claimed victory, but Bean has yet to concede. There are several thousand absentee and provisional ballots still to be counted, and the deadline for reporting the final results is Nov 16. This one doesn't look good for the Democrats, as the majority of outstanding ballots are from counties that Walsh won. The 8th Congressional District includes Schaumberg and the suburbs northwest of Chicago.

Kentucky 6th CD: Republican challenger Andy Barr formally requested a "recanvass" or machine check of the vote totals Thursday afternoon. Barr trails Rep. Ben Chandler (D) by 644 votes, out of about 239,000 votes cast. Chandler has claimed victory, but the recanvass will take place Nov. 12. Barr can also petition for a more intensive hand recount, but his campaign would have to foot the bill at a cost of several thousand dollars. Experts say it's unlikely Barr can overcome a 600-plus-vote deficit. The 6th Congressional District, in central Kentucky, includes Lexington and its surrounding counties, stretching west to include the capital of Frankfort.

New York 25th CD: This one might not be decided until Thanksgiving. Republican challenger Mary Ann Buerkle has moved into the lead, after late results on Wednesday from Wayne County were finally reported. The results had been delayed because of machine problems. Buerkle now holds a 659-vote lead over incumbent freshman Dan Maffei (D). More than 11,000 absentee ballots are still to be counted, most of them from Onandaga County, which is where the majority of voters live and the only county that Maffei won. The 25th Congressional District is in the middle of upstate New York and includes the city of Syracuse and the communities west between Syracuse and Rochester.

Texas 27th CD: Twenty-eight-year incumbent Solomon Ortiz (D) has refused to concede, despite trailing challenger Blake Farenthold by 799 votes out of more than 100,000 votes cast. Farenthold, a lawyer and conservative radio talk show host from a famous Democratic family, has declared victory. Ortiz and his team of lawyers are considering a recount, which his campaign would have to pay for. The 27th Congressional District is in southeast Texas, stretching from Corpus Christi south to the border, including Brownsville.

Virginia 11th CD: Rep. Gerry Connolly (D) extended his lead over businessman Keith Fimian (R) to 930 votes, according to the latest tally released Thursday afternoon. Connolly, a freshman Democrat, doubled his lead from election night, when he led by only 487 votes out of just over a quarter million votes cast. Fimian has not conceded the race and is considering requesting a recount. Since the margin is greater than .05 percentage points, Fimian would have to pay for a recount, although news reports say he'd have little trouble soliciting donations for that effort. Any recount would not start until at least Nov. 22, when the results are certified. The 11th Congressional District is in northern Virginia and includes the outer western suburbs of Washington DC.

Washington 2nd CD: Five-term incumbent Rep. Rick Larson (D) jumped out to a 1,606-vote lead Thursday over challenger John Koster (R) out of almost 200,000 votes counted so far. Koster had a 1,500-vote lead on election night, but as mail-in ballots trickle in Larson has steadily gained ground. But there are still a substantial number of ballots outstanding, many from Snohomish County, which is Koster's stronghold. As is customary in close races in this mail-in ballot state, both campaigns will wait for several more days before declaring victory. The 2nd Congressional District in the northwest part of the state, and includes the San Juan Islands and the mainland along Puget Sound north of Seattle.

Washington 9th CD: Rep. Adam Smith (D) leads his challenger by 11,366 votes, which computes to 53%-46%. NBC News has projected Smith the winner. But because Washington is a mail ballot state, it might be a few more days before things are finalized. The Republican in the race is state legislator Dick Muri. The 9th Congressional District is in the independent-heavy corridor between Seattle and Tacoma.

NOTE: North Carolina 2nd CD: Longtime incumbent Bobby Etheridge (D) closed to within 1 percentage point and plans to seek a recount if the margin remains that close. His Republican challenger, Renee Ellmers, leads by 1,646 votes. Ellmers on Thursday afternoon blasted the NRCC for allegedly refusing to help pay attorneys in the potential recount battle; she claims she'll face legal costs of at least $50,000. Etheridge picked up about 500 votes yesterday, bringing him within the margin eligible for a recount. NBC News has projected Ellmers as the winner, though Etheridge has not conceded.